I entirely forgot about my radiator for a while, I've been working on a couple of drive train issues.
Kinda unrelated bu thow did you mount the rad ? Alum doesn't do well flexing & will quickly crack if mounted ridgid to the body , all factory cars will alum rads use rubber mounts to isolate body flex .
Currently my radiator is not mounted, the shroud got bent during shipping and had to get sent back. I should have taken some measurements before I sent it back, because without it I cant tell if it will conflict with my battery tray.
I do like the idea of the grommets. For that I was thinking: bolt, washer (larger in diameter then grommet), grommet, radiator, two nuts. I'd hate for the grommet to come out.
I know it isn't factory, but I always use a Negative battery cable that has a ground pigtail off of it that I connect at the front headlight harness grounding bolt, by the battery tray. It is right next ti the radiator. Never had any stray volatges. I also put a ground stray from the rear of the driver's side head to the frame under my feet.
If you remember basic electronics, electrons flow negative to positive. Our grounds are actually powering everything, so I treat them as a supply. Switches on the positive side are simply a valve to let the electrons flow back to the battery.
Think of it this way and you'll never have a problem.
Although my radiator isn't mounted it is grounded. They should of slapped the heck out of whoever assigned the conventional current to be out of the positive and into the negative!
Back when my car wouldn't start when I first started to redo my harness I spoke to some guys at my local auto shop. Their response was they charge $121/h, they gave me some pointers for free and I had it going that day. There other speciality is radiators. I spoke to them again today, got the same response about the money and they gave me some more free pointers. This is a business that has a serious aversion to accepting money! Apparently the most common cause for stray current is acid/base imbalances in the radiator fluid. This comes from putting in new fluid or in particular changing for green to red fluid which was recommended for my Aluminium radiator. Apparently using radiator flush and draining isn't enough to balance out the old fluid. So the theory is, the guys have only ever seen two genuine cases of stray current and that I should leave the car be for two or so weeks and occasionally run the engine to mix the fluid around and it should resolve it self! It all working it self out sounds good to me.
Thanks for the help so far